Stress-Related Tinnitus Treatment Protocols

The neurophysiological model is based on the idea that conditioned fear responses elicited by the tinnitus precept are the cause for tinnitus becoming bothersome.

8.3.3 The Cognitive Model

A conceptual cognitive model proposed by McKenna et al. (2014), incorporates a cognitive model of distress to explain tinnitus-associated insomnia (Harvey 2002). McKenna et al. argue that the tinnitus-signal distress and bodily arousal are provoked mainly through negative cognitive misinterpretations, leading to inaccurate evaluations of sensory activity and distorted perceptions (see Fig. 8.2). It is proposed that the resulting stress and hypervigilance contribute to a feedback cycle that exacerbates the distress associated with flawed sensory processing, of which tinnitus may be a major component. The model attributes a fundamental role to the negative evaluation of tinnitus. The negative evaluation of the tinnitus percept can be viewed as comprised of primary and secondary appraisals. For example, a person might initially appraise the tinnitus as being threatening to their health and then make a secondary appraisal of their (in)ability to cope with it.

The cognitive model attributes a fundamental role to the negative evaluation of tinnitus.

Clinical trials in which this model is applied to treatment, by which the clinical relevance of the model can be tested, have not taken place yet. However, evidence exists that cognitive processes, such as interpretation, attention, and memory, are indeed involved in chronic tinnitus suffering (Andersson et al. 2013; Conrad et al. 2011; Rossiter et al. 2006; Stevens et al. 2007), though these studies were not specifically aimed at validating the model.

8.4 The Cognitive Behavioral Approach

Several so-called “cognitive behavioral” accounts for tinnitus have been postulated (Cima et al. 2011a; Hallam et al. 1984; Kleinstauber et al. 2012; McKenna et al. 2014). A promising one is based on a fear-avoidance model (FA model) of chronic pain (Vlaeyen and Linton 2000, 2012), since in this model, predictions about the behavioral components in the maintenance of tinnitus distress are included. The FA model (Fig. 8.3) for chronic tinnitus offers explanatory predictions about both the cognitive processes and the behavioral mechanisms. It predicts that individuals perceiving the tinnitus signal are subject to automatic emotional and sympathetic responses. These symptoms are misinterpreted as harmful or threatening. If the signal persists, the coinciding threatening (alarm) states, which indicate malignance of the signal, elicit conditioned, both classical and operant, fear responses, i.e., fear, increased attention, and safety seeking, i.e., avoidance and escape behaviors. These safety behaviors become negatively reinforced through instant decreased fear, which is adaptive in the acute phase. In other words, by avoiding, or not exposing themselves to tinnitus-related perceptions, patients learn that their fear instantly diminishes. However, in the long run, through persistent avoidance of tinnitus percept as well as tinnitus-eliciting or tinnitus-increasing stimuli, the heightened fear and fear responses, such as hypervigilance and safety seeking, are maintained. Avoidance behaviors subsequently lead to task interference and functional disability (Blaesing and Kroener-Herwig 2012; Hesser et al. 2009). The maintained high threat value of the tinnitus leads to increased tinnitus severity and distress, feeding into an endless circle of increased disability (Cima et al. 2011b).

Fig. 8.3

The fear-avoidance model

The cognitive behavioral model predicts that the tinnitus signal invokes automatic sympathetic and emotional responses, which are misinterpreted as harmful or threatening, leading to safety behaviors.

A typical feature of the FA model is its prediction; next to the maladaptive pathway (leftward), an alternative and more adaptive pathway (turning right) is proposed, whereby a positive or neutral evaluation of the tinnitus results in no or low fear of the tinnitus and in partially or completely decreased distress. In other words, the tinnitus sound is accepted by the system as being benign; therefore, no unwanted attentional resources are needed. In turn, avoidance and/or escape behaviors do not interfere with daily tasks, resulting in lack of severe disability due to tinnitus.

8.5 Comparing the Models

In overview, consensus among the theoretical models exists regarding the evidence that a neutral acoustic signal receives negative valence by means of classical conditioning, in which an individual learns that the signal becomes predictive for negative states (“false alarms”) as a result of automatic negative responses elicited by this signal (Pawel J. Jastreboff and Jastreboff 2006; Vlaeyen and Linton 2000). Both cognitive models highlight the importance of cognitive processes, and although behavioral consequences are mentioned and recognized as important, they are considered secondary for the maintenance and therefore also for the treatment of chronic tinnitus suffering. Conscious cognitive processes are emphasized, as these constitute the main therapeutic targets in treatments stemming from these models, hypothesizing that the classical (involuntary) learning mechanisms are of lesser importance.

Following the lines of theoretical reasoning, it can be postulated that conditioned negative responses are the main cause of the suffering (Jastreboff and Jastreboff 2006) and that these aversive responses toward the tinnitus sound lead to misinterpretations feeding back into negative evaluations and fear responses (Hallam et al. 1988; Hallam et al. 1984; P. J. Jastreboff 2007; McKenna et al. 2014). Building on these principles, the FA model offers predictions about fearful responses (emotional and attentional) and behaviors (Cima et al. 2011a), which explain the maintained tinnitus distress. This latter premise is based on an operant component in learning theory terms and remains unexplained, though mentioned, both in the neurophysiological model as well as the cognitive model. The FA model provides specific predictions on this level, which leads us to the main difference between the models.

While the NP model deals mainly with tinnitus generation and detection and the habituation and cognitive models emphasize the voluntary conscious processing of the tinnitus, the FA model is predictive beyond that and picks up there where the other models stop being explanatory. The main conceptual overlap might lie at the level of the detection/perception and interpretation level, and the classical learning principles are involved purportedly, as was described above. The models differ in explaining how these learning principles—both classical and specifically the operant learning mechanisms—may play a role. The NP model is mainly based on neurophysiological processes and attempts to explain the psychological path in neurophysiological terms. This provides only general descriptions of classical and operant conditioning mechanisms. The habituation and cognitive models both state that the conscious alteration of negative interpretations will decrease arousal and distress as a result of tinnitus, with less emphasis on the behavioral processes. As opposed to this, the FA model is based on associative learning and operant principles and offers explanatory predictions about the classical and the behavioral mechanisms. This fear-avoidance approach integrates previous concepts and might prove helpful in discovering new venues of investigations, as well as in offering means to determine why not only cognitive but also behavioral treatment approaches are repeatedly found to be successful (Tutorial 8.1).

Tutorial 8.1 Theoretical models

Theoretical models leading to psychological treatment approaches for tinnitus distress can be roughly divided into two categories: the cognitive approaches and the cognitive behavioral approaches

Cognitive approaches

Neurophysiological model

Main hypothesis

Dysfunction is hypothesized on the following levels

• Detection

• Perception/evaluation

Based on two fundamentals of brain functioning in general

1. Plasticity

2. Habituation

Hallam’s habituation model

Main hypothesis

Malfunctioning attentional processes disturb habituation

McKenna’s cognitive model

Main hypothesis

Cognitive appraisal of the tinnitus signal and selective attention distort the tinnitus perception

Cognitive behavioral approaches

Fear-avoidance model

Main hypothesis

Safety behaviors, negatively reinforced in the short term (instant temporary decrease in fear), maintain tinnitus complaints (maintenance of underlying fear)

8.6 Treatment Approaches for Tinnitus-Related Distress

Next to the theoretical frameworks, a short overview of developments within the cognitive behavioral therapies (CBT) during the past decades is necessary, to provide the background for the development of treatments for reducing tinnitus-related distress. To answer the question as to what is meant by the cognitive behavioral therapies, we will take a short journey in the past.

8.6.1 The History of CBT

The first wave of CBT, or the first revolution, started with Wundt’s (1832–1920) experimental methods and findings, in combination with the emergence of the behavioral traditions of the classical- or respondent- (Pavlov 1927) and operant- or instrumental- (Skinner 1938) conditioning principles. A class of psychological interventions emerged and converged theory, evidence, and experimental methods. Noteworthy is that at that time, it was a new and a very exciting field in psychology.

A second major impulse was given by the so-called cognitive revolution (second wave), not surprisingly by cognitive sciences and entailed the empirical study of how the thinking (cognitions) and the interpretations (attributions) affected the emotions and behavior. Methods were mainly aimed at the conscious and voluntary altering of interpretations and thought processes, by means of elaborate narrative therapeutic methods (cognitive therapy). Examples include rational emotive therapy (RET) introduced by Albert Ellis in the 1950s, which focused on the associations between cognitions and emotions (Ellis and Grieger 1977). Aaron Beck (1976) introduced cognitive therapy (CT) for the identification and modification of thought “errors” (Gopinath et al. 2010). Another major influence on the cognitive revolution was the major discoveries in computer science and programming, where a computer software gave almost a perfect analogy for understanding the “programming rules” in human brains. During the early 1970s, the behavioral and cognitive approaches merged (Dobson 2010; Hofmann et al. 2012), and the term “integrated cognitive behavior therapies” (CBT) was invented.

The new CBT treatments, such as mindfulness-based stress reduction (MBSR), or simply mindfulness, and acceptance and commitment therapy (ACT), have been classified as “third-wave” CBT approaches (Dobson 2010; Hayes 2004). Some discussion exists as whether they are a new form of therapy altogether, or whether they are still grounded within the traditional CBT family (Ost 2008). For the purpose of this chapter, they will be considered the third revolution in CBT. Although the third-wave CBT treatments contrast with the cognitive tradition by accepting the existence of negative thoughts and emotions rather than trying to modify them, a major similarity is the assumption that human suffering is caused by learning, dysfunctional beliefs, and behavior, all leading to emotional distress and disability. Effects of both ACT and MBSR have been investigated in different populations, including patients with different psychological disorders (e.g., anxiety and depression), with chronic symptoms (e.g., chronic fatigue and chronic pain), and in the healthy population (Bohlmeijer et al. 2010; Powers et al. 2009; Veehof et al. 2011).

The cognitive behavioral therapies (first, second, and third wave) share the idea about psychological distress and resulting problems being based in malfunctioning information processing, emotional reactivity, and behavioral mechanisms. CBT has led to a plethora of evidence-based cognitive behavioral treatments for mental and somatic health disorders (Hofmann et al. 2012). In sum, CBT is an integrative and pragmatic treatment approach aimed at modifying dysfunctional behaviors and beliefs in order to reduce symptoms, increase daily life functioning, and ultimately recover from the disorder (Dobson 2010).

8.6.2 Tinnitus Retraining Therapy

Although tinnitus retraining therapy (TRT) is not usually categorized as a form of CBT, it is nevertheless a treatment with a main cognitive component and is therefore at least in part a form of first–wave CBT.

As was introduced earlier, TRT is the implementation of the NP model, which is a theory of neurophysiological processes considered to be relevant for tinnitus perception. TRT is based on two fundamental principles of brain functioning: (1) plasticity and (2) habituation. The basis of the NP model is that the actual source (the tinnitus sound) is not causing the annoyance, but it is the subjective experience and interpretation of the individual which determine whether the tinnitus is experienced as aversive or not.

Two main components make up TRT. The first component is a form of cognitive therapy, so-called retraining counselling or teaching. Through verbal instruction patients are expected to reinterpret the tinnitus, thereby decreasing negative thoughts and beliefs about the tinnitus. The second entails sound therapy, which is either instructing the patient to wear tinnitus maskers1 or to enrich sound environment, avoiding silence at all costs. It is hypothesized that sound therapy (and avoidance of silence) will decrease the detection of tinnitus and therefore facilitate sustained habituation (Jastreboff and Jastreboff 2000). Changes in tinnitus interpretation and evaluation are postulated to be generated automatically by instruction and sound enrichment. The resulting emotional and behavioral consequences are not the aim of therapy, nor are there specific predictions about these in the NP model. Additionally, TRT postulates that once the conditioned associations are removed, by said interventions, habituation should occur (Jastreboff and Hazell 2008). Although there is a specific prediction about what is the unconditioned stimulus, the conditioned stimulus and conditioned responses are not clearly specified in the NP model (Cima 2013). The effectiveness of TRT remains inconclusive (Hoare et al. 2011; Hobson et al. 2010; Phillips and McFerran 2010), though TRT, and specifically the use of sound generators, is still a popular form of treatment for tinnitus distress, mainly among audiologists.

8.6.3 Cognitive Therapy and Cognitive Behavioral Therapy

Confusion often exists about the differences between cognitive and cognitive behavioral therapy (CBT), since both terms are used interchangeably. Since CBT stems from the convergence of two distinct theoretical schools, the radical behavioral school (first wave) and the cognitive school (second wave), CBT entails a diversity of both cognitive and behavioral principles and methods, and usually a combination of these is used in therapeutic sessions. Therefore, both cognitive and behavioral treatment elements can be found when reviewing CBT procedures in general as well as in tinnitus intervention. Cognitive behavioral theory and treatment has been applied in tinnitus research for decades (Hallam et al. 1988; Scott et al. 1985; Sweetow 1986), and CBT approaches for tinnitus have been repeatedly shown to be effective in decreasing tinnitus distress, anxiety, and tinnitus annoyance and improving daily life functioning. Although there are the discernible common elements across CBT-based treatments for tinnitus, the investigated tinnitus CBT approaches vary in numbers of treatment sessions, hours spent in therapy, group versus individual formats, face-to-face versus internet based self-help therapies, combinations of different treatment elements, and tinnitus diagnostics and outcome assessments.

8.6.4 The Cognitive Approach

In line with the evolution of CBT in general, during the development in CBT for tinnitus, cognitive therapeutic procedures have been applied plentifully. The main idea of the cognitive approach is that psychological distress is maintained by cognitive factors. Typical cognitive therapeutic interventions (or so-called “talking” therapy) are aimed at (Ellis and Grieger 1977; Beck 1976):

Dealing with current problems and thought processes (and not so much with the past)

3.

Advising the patients to perform behavioral experiments in order to test the validity of maladaptive thoughts and beliefs

In line with the cognitive tradition, the cognitive model (McKenna et al. 2014) postulates that therapeutic strategies used to change maladaptive cognitions lead to automatic changes in emotional distress and in problematic behaviors. These cognitive techniques seem to be helpful in the short term. Techniques, next to educational counselling, include but are not limited to “Socratic dialog,” thought control, rational thought formulation, exploring automatic thoughts, and testing of thoughts and beliefs through behavioral experiments.

8.6.5 A Fear-Avoidance Approach

Recently, exposure therapy, which is a behavioral therapeutic strategy, entered CBT treatment protocols for tinnitus (Cima et al. 2012), next to the much more known cognitive (“talking”) interventions. Exposure therapy, also applied in chronic pain CBT treatments (Volders et al. 2011), is a clinical application of what is called “extinction” of the association between two stimuli in classical terms of learning theory. It is assumed that tinnitus patients learned to be fearful of the tinnitus percept. That is, in the distressed tinnitus patients, the initially neutral tinnitus signal became associated with sympathetic arousal (alarm detection) (Jastreboff 1990; Wilson 2006). According to fear-avoidance reasoning (see Fig. 8.4), the neutral tinnitus signal (CS) became a predictor of aversive interoceptive stimuli (US), hereby receiving a very negative value (danger). Patients interpret the signal as a sign of harm or injury, which is why they are so fearful, selectively single out the tinnitus signal, are interrupted, and engage in safety-seeking behavior (CR). These mechanisms are likewise at work in arachnophobias, for example. The spider, which is harmless, becomes a sign of great danger, leading to the extreme fear.

Fig. 8.4

A new fear-learning paradigm: applying the classical conditioning to tinnitus-related distress (Cima 2013)

For arachnophobia, exposure procedures consist of repeated confrontations with spider-related images, objects, and eventually real spiders, which evoke the greatest fear in the patient. As a result of repeated exposure to the most feared stimuli, the patient learns that confrontation with spiders is not life-threatening, and therefore they are not in danger. In the end, the fear of spiders dissipates (extinction). Analogically speaking, tinnitus patient is extremely fearful of perceiving the tinnitus. Even though the tinnitus is continuously present, the involuntary response is to not hear it and to try to be minimally confronted with the tinnitus sound (avoidance). Patients do this by trying to control sound environment, or not thinking about tinnitus (which is contradictory: “white bear effect”), and direct their attention elsewhere, but consequently they increase the monitoring and awareness of tinnitus. Cognitive resources by consequence are depleted, leading to task interruptions, more avoidance (safety seeking), and eventually disruptions in functional activities. The sustained consequences are severe disabilities disrupting all life domains and severe dysphoria (dissatisfaction with life).

This “new” form of CBT for tinnitus typically includes the third-wave forms of therapy (see Tutorial 8.2) to enhance internal observations, to increase moment-to-moment consciousness (exposure to) of the tinnitus, and to provide the ability of observing tinnitus-related emotions, sensations, and cognitions in a nonjudgmental way. Exposure therapy for tinnitus patients involves exposing them to their tinnitus sound, the interceptive sensations associated with the tinnitus, as well as their moment-to-moment narrative. In order to provide an appropriate context, exposure is performed in quiet circumstances. This way, the patient experiences that the tinnitus sound is harmless, not dangerous, and listening to it in silent environments will not have catastrophic consequences. They also learn that the aversive interoceptive stimuli are not always triggered and threat expectancies are adjusted. These experiences lead to a neutralization of tinnitus by extinction of tinnitus-related fears; consequently the more the tinnitus becomes less intrusive and bothersome, the more they engage in exposure. In classical learning theory terms, if the patients are exposed to the conditioned stimulus, without the unconditioned stimulus always occurring, extinction of the unwanted conditioned responses occurs (see Fig. 8.4).

8.6.6 Comparing the Treatments

As has been stated before, the theoretical frameworks are fundamentally based on the idea that the initially neutral tinnitus signal receives an “alarm” value, through classical conditioning. In turn, this negative tinnitus valence exacerbates negative responses in cognitions, emotions, and behaviors, hindering the “normal” process of habituation. Tinnitus distress—which is the very negative and aversive state—arises when processes of adaptation and the efforts to that have failed to return the organism to equilibrium or homeostasis.

Important to note is that the treatment avenues have been contradictory. The TRT approach suggests that next to extensive education, a (partial) masking of the signal (avoidance of the signal, by avoiding silence at all costs) is the road to habituation. The habituation model and cognitive approaches reason that thought control and attention diversion techniques (altering thoughts/beliefs about the tinnitus and actively directing attention away from the tinnitus) will be beneficial for habituation. For a short-term habituation, these strategies might be useful.

On the other hand, the FA approach leads to the complete opposite approach. The FA’s main aim is extinction of CS-US associations and therefore sustained extinction of conditioned responses, instead of enforcing short-term habituation. If we look at Fig. 8.4, the FA approach aims at dissolving the dotted arrow between the CS and US.

Tutorial 8.2 The “third-wave” CBT treatments

Mindfulness-based stress reduction (MBSR)

Mindfulness is a type of psychological treatment aimed at psychological distress, depressive symptoms and anxiety, initially developed for individuals suffering from chronic disease. MBSR was developed by Kabat-Zinn (1982), Ludwig and Kabat-Zinn (2008). MBSR protocols typically consist of up to 10 group sessions. The focus lies on training of the skill of being mindful, which is a moment-to-moment awareness, and observing emotions, sensations, and cognitions nonjudgmentally. Sessions are built up around meditational skills, bodily exercises, and psycho-education. Initially MBSR was developed for chronic pain sufferers and later adapted for chronic diseases such as heart disease and recently for tinnitus as well (Bohlmeijer et al. 2010; Kauth et al. 2010; Philippot et al. 2012). As a stand-alone treatment approach, mindfulness has been applied to a large number of psychological disorders (Fjorback et al. 2011; Shapiro et al. 2011). Mindfulness is also an important component of other psychological treatments such as ACT, some forms of behavioral treatment, and cognitive therapy (Hayes et al. 1999, 2006; Teasdale et al. 2001)

Acceptance and commitment therapy (ACT)

According to its founder (Hayes et al. 2006), ACT has its roots in the behavioral tradition. Interestingly, ACT does not emphasize the accuracy or the content validity of cognitions and behaviors, as is the case in the more cognitive approaches, described earlier. Focus in ACT lies on functional usefulness of thoughts and actions and not on the “right- or wrongfulness” (Hayes et al. 2006; Hofmann et al. 2010). One of the key elements of ACT is to decrease “experiential avoidance” (Hayes and Wilson 1994); i.e., ACT advocates experiencing psychological events (thoughts, perceptions, emotions) in a nonjudgmental way, not trying to change or modify those events, leading to a more functional awareness of how thoughts, emotions, and behaviors create and maintain distress. Since MBSR approaches advocate present moment awareness and observation in a nonjudgmental way, which results in decreased rumination and worry, it has been an integrated part of the ACT protocol

In other words, the FA model contradicts the habituation approaches by predicting that doing the exact opposite (confrontation instead of avoidance, exposure instead of masking, tinnitus awareness instead of attention diversion, observing thoughts/beliefs instead of altering/challenging) will lead to sustained recovery of distress. Indeed, strong associations between avoidance behaviors and perceived tinnitus handicap have already been found (Kleinstauber et al. 2013).

8.7 Measuring Tinnitus-Related Distress

As it has been described in the previous sections of this chapter, distress is an aversive state, which is the result of the organism failing to adapt to stressors. Tinnitus-related distress, and the treatment thereof, hardly focusses on the tinnitus sound itself, since indeed emotional distress is the main and the most significant factor in predicting the variability in quality of life of tinnitus patients is psychological distress (Cima et al. 2011a, b; Erlandsson and Hallberg 2000). In individuals with persistent tinnitus, the acoustic characteristics of tinnitus percept (e.g., loudness or pitch) are hardly associated with tinnitus severity or treatment outcome (Jastreboff 1990; Jastreboff and Hazell 1993). The initial negative evaluation and subsequent fear responses leading to the overall distress might be more relevant in defining the severity of complaints than the tinnitus percept itself.

8.7.1 Tinnitus Severity in Terms of Distress

Tinnitus severity can be defined as a function of the level of averseness of the state tinnitus patients are in, in other words, the level of distress. As mentioned earlier, only for a small group of patients (3–8%), tinnitus is distressing and therefore disabling (Davis and Refaie 2000; Ahmad and Seidman 2004). Since distress is a term which coins the general aversive state, instruments to measure this construct usually include subdomains, which are hypothesized to be of importance for tinnitus severity. These instruments are therefore hybrid in that they measure several concepts as a means to capture tinnitus distress. There are several instruments in use for assessing the level of severity of tinnitus complaints. In a review on disease-specific health-related quality of life (HR-QoL) instruments used to measure outcomes in tinnitus trials, six commonly used HR-QoL tinnitus instruments were identified (Kamalski et al. 2010; Meikle et al. 2007) and will be shortly described below. The instruments specifically used to measure the outcome of treatment are described in Chap. 9.

The Tinnitus Handicap Inventory (THI) (Newman et al. 1996) is an instrument that presumably measures the impact of tinnitus on a daily life. It has three subscales, functional, emotional, and catastrophic responses to the tinnitus, the second being psychological distress related. Both overall and subscale internal consistency were found to be good. The Tinnitus Questionnaire (TQ) (Hallam et al. 2004) has six predominantly distress-related domains: emotional distress, cognitive distress, intrusiveness, auditory and perceptual difficulties, sleep disturbances, and somatic complaints as a result of the tinnitus. The TQ items are internally consistent; however, the subscales lack internal consistency. The Tinnitus Reaction Questionnaire (TRQ) (Wilson et al. 1991) was intended to specifically measures distress related to tinnitus. TRQ incorporates four different domains: general distress, interference, severity, and avoidance of the tinnitus. The three questionnaires focus mainly on measuring patient’s perception, on impaired individual functioning, or on specific functions as a result of tinnitus.

The Tinnitus Severity Index (TSI) (M.B. Meikle et al. 1995) was introduced as a unified measure of tinnitus severity. Two items specifically address the interference of the tinnitus in daily life activities. The Tinnitus Handicap Questionnaire (THQ) (Kuk et al. 1990; Meikle et al. 1995) was intended to measure patient’s perceived degree of handicap due to tinnitus. The THQ has three domains: physical health/emotional status/social consequences, hearing and communication, and personal viewpoint on tinnitus. Seven items specifically address the interference of tinnitus on the daily activities: four of them address hearing difficulties, two address social interactions, and one item addresses sleep difficulties due to tinnitus. The THQ subscales fails on internal consistency.

The Tinnitus Severity Questionnaire (TSQ) (Coles et al. 1991) is a short unified measure, with two items specifically addressing interference of tinnitus, one item regarding sleeping habits and one the impairment of concentration.

More recently, the Tinnitus Functional Index (TFI) was introduced as a new measure for scaling the severity and negative impact of tinnitus, both for use in diagnostic assessment and for measuring treatment-related changes in tinnitus (responsiveness) (M. B. Meikle et al. 2012; Henry et al. 2014). What is unique about this instrument is that it is a measure of tinnitus severity as perceived “over the last week,” therefore asking patients to reflect about only a short timeframe (1 week). The TFI is also a hybrid, measuring tinnitus-related distress/severity as a function of predominantly psychological construct such as attention, worry, anxiety, and depression as well as the more functional constructs such as hearing, social life, and activity level. Table 8.1 lists these seven instruments along with their characteristics and psychometric quality.